Suppressing the formation of tin vacancy yields efficient lead-free perovskite solar cells

Novel PHA Organic Spacer Increases Interlayer Interactions for High Efficiency in 2D Ruddlesden–Popper CsPbI3 Solar Cells

“… − To explore whether there is an N–H ··· I hydrogen-bonding interaction between organic spacer cations (PA + and PHA + ) and inorganic [PbI 6 ] 4– octahedron layers, FTIR characterization of PA-Pb and PHA-Pb films was performed (Figure b). Compared with the PA-Pb film, the intensity of the υ N–H peak in the PHA-Pb film is enhanced and shifts to a lower wavenumber, which indicates the existence of N–H ··· I hydrogen-bond interactions between −NH 3 + and the inorganic layer. ,, The H nuclear magnetic resonance ( 1 H NMR) in Figure c shows that the −NH 3 + signal of PHA appears at 9.88 ppm, and after the formation of the PHA-Pb perovskite, its −NH 3 + signal exhibits an obvious chemical shift and moves to 8.09 ppm, which is further evidence of hydrogen bonding. , Similar phenomena were also observed in the 1 H NMR spectra of PA powder and PA-Pb film (Figure S2a).…”

“…In addition, the dark J – V curves of the PA-Pb and PHA-Pb devices show that the PHA-Pb device has a smaller dark short-circuit current density ( J SC ), suggesting that the N–H-group-rich PHA spacer helps reduce defects in the films, resulting in a low leakage current (Figure f) . However, the bias current is higher in reverse bias, which probably originates from the holes and small grain sizes from the organic spacer introduction and limits the quality of films. , …”

“…48 However, the bias current is higher in reverse bias, which probably originates from the holes and small grain sizes from the organic spacer introduction and limits the quality of films. 4,27 Benefiting from the role of N−H•••I hydrogen-bonding interactions in optimizing film morphology and optoelectronic properties, we fabricated photovoltaic devices based on the structure of FTO/TiO 2 /2D RP CsPbI 3 /Spiro-OMeTAD/ MoO 3 /Ag. The corresponding J−V curves of PA-Pb and PHA-Pb devices are shown in Figure 4a.…”

Raising the LUMO level of fullerene derivatives alleviates the output voltage loss in tin halide perovskite solar cells

“…As shown in Fig. 3d, the flat band potential ( V bi ) was increased from 0.56 V for the device with PC 61 BM to 0.82 V for the C 60 -ETPA device, 29 which facilitated the improvement of V oc .…”

Dimensional Tailoring Endows Tin Halide Perovskite Solar Cells with High Efficiency and Stability

“…Zhao et al achieved a maximum PCE over 8% with a V oc of 0.61 V with FA 0.75 MA 0.25 SnI 3 . [49] However, these efforts still do not address the stability issue. It is exciting that incorporating larger organic spacer cations into 3D tin perovskites to form low-dimensional tin perovskites exhibited remarkable stability even under humid air.…”